Thermoplastic resin composition containing a modified polyphenylene ether

ABSTRACT

There are disclosed a thermoplastic resin composition comprising (A) a styrenic polymer having a high degree of syndiotactic configuration, (B) an inorganic filler and (C) a polyphenylene ether that is modified with a compound having an ethylenic double bond and a polar group in the same molecule, especially maleic anhydride, the ether having a modification rate of 1.3% or more by weight; a thermoplastic resin composition further comprising (D) a rubbery elastomer in addition to the above components (A), (B) and (C); a process for producing modified polyphenylene ether (PPO) comprising reacting 100 parts by weight of PPO with 1 to 20 parts by weight of the above compound or a derivative thereof in an aromatic hydrocarbon solvent in the presence of 15 or less parts by weight of a radical generator; and a process for producing the modified PPO comprising reacting 100 parts by weight of PPO with 1 to 5 parts by weight of the above compound or a derivative thereof at 300° to 350° C. in the presence of 0.1 to 3 parts by weight of a radical generator which exhibits a half-life period of 1 minute at 300° C. or higher. The above thermoplastic resin composition is markedly improved in its dynamical properties especially rigidity and heat resistance.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a thermoplastic resin composition. Moreparticularly, it pertains to a thermoplastic resin composition whichcomprises as the principal component a styrenic polymer having a highdegree of syndiotactic configuration, said composition being improved inlong-term heat resistant stability by being compounded with apolyphenylene ether that is modified by a compound having an ethylenicdouble bond and a polar group in the same molecule (particularlytypified by maleic anhydride) or a derivative thereof at a modificationrate of not less than 1.3% by weight (hereinafter sometimes referred toas "Maleic anyhydride-modified PPO" or simply "Modified PPO"), and atthe same time, to a process capable of efficiently producing the Maleicanhydride-modified PPO.

2. Description of Related Art

There has heretofore been adopted the technique for improving variousthermoplastic resins in the dynamical properties (or mechanicalproperties), especially rigidity and heat resistance by compoundingtherein an inorganic filler such as glass fiber. There are proposed thethermoplastic resin compositions excellent in heat resistance anddynamical properties, for example, in Japanese Patent ApplicationLaid-Open Nos. 257948/1987 and 182344/1990 in which syndiotacticpolystyrenes are compounded with an inorganic filler, and athermoplastic resin and/or rubber together with an inorganic filler,respectively. However, the aforesaid technique has been incapable ofproducing a satisfactory resin composition even if compounded with aninorganic filler because of the insufficient adhesivity between asyndiotactic polystyrene (SPS) and an inorganic filler.

Such being the case, Japanese Patent Application Laid-Open No.126743/1991 discloses the improved technique over the aforementionedones in which a syndiotactic polystyrene is incorporated with a maleicanhydride-modified PPO to provide a resin composition excellent inimpact resistance, heat resistance and mechanical properties. Theaforesaid improved technique, however, necessitates at least 5% byweight of the maleic anhydride-modified PPO to be incorporated thereinfor the purpose of sufficienty exhibiting the effect owing to its lowmodification rate.

Nevertheless it has been found, as a result of long-term heat resistancetest for the resin composition incorporated with the maleicanhydride-modified PPO, that the decrease in the molecular weight of thesyndiotactic polystyrene (SPS) is made remarkable by the increase in theloading of the maleic anhydride-modified PPO causing deterioration ofdynamical properties of the composition, and that a loading thereof of5% by weight or more further accelerate the aforestated unfavorabletendency. Moreover in order to allow an alloy-based resin compositionincorporated with polyamide to exert a sufficient compatibility effect,it is necessary to add a large amount of maleic anhydride-modified PPOto the composition, thus lowering the crystallinity of SPS. Likewise,the decrease in the molecular weight of SPS is inevitable in thelong-term heat resistance test for the composition.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a thermoplasticresin composition excellent in dynamical properties, especially rigidityand long-term heat resistance which is produced from a styrenic polymerhaving a high degree of syndiotactic configuration compounded with aninorganic filler such as glass fiber.

It is another object of the present invention to provide a thermoplasticresin composition excellent in dynamical properties, especially rigidityand long-term heat resistance which is produced from a styrenic polymerhaving a high degree of syndiotactic configuration compounded with aninorganic filler such as glass fiber and a rubbery elastomer.

It is still another object of the present invention to provide a processfor producing a Maleic anhydride-modified PPO to be effectivelycompounded in the above-mentioned thermoplastic resin composition.

Specifically the present invention provides as the first aspect thereofa thermoplastic resin composition which comprises (A) 100 parts byweight of a styrenic polymer having a high degree of syndiotacticconfiguration, (B) 1 to 350 parts by weight of an inorganic filler and(C) 0.1 to 3.5 parts by weight of a Maleic anhydride-modified PPO havinga modification rate of 1.3% or more by weight.

In addition, the present invention provides as the second aspect thereofa thermoplastic resin composition which comprises (A) 100 parts byweight of a styrenic polymer having a high degree of syndiotacticconfiguration, (B) 1 to 350 parts by weight of an inorganic filler, (D)5 to 100 parts by weight of a rubbery elastomer and (C) 0.1 to 3.5 partsby weight of a Maleic anhydride-modified PPO having a modification rateof 1.3% or more by weight.

Moreover, the present invention provides as the third aspect thereof aprocess for producing a Maleic anhydride-modified PPO having amodification rate of 1.3% or more by weight which comprises reacting 100parts by weight of a polyphenylene ether consisting of the repeatingunits each represented by the general formula (I) ##STR1## wherein R¹and R² are each an alkyl group having 1 to 4 carbon atoms or a halogenatom, with 1 to 20 parts by weight of a compound having an ethylenicdouble bond and a polar group in the same molecule or a derivativethereof in an aromatic hydrocarbon solvent in the presense of 15 or lessparts by weight of a radical generator (Process I ).

Furthermore, the present invention provides as the fourth aspect thereofa process for producing a Maleic anhydride-modified PPO having amodification rate of 1.3% or more by weight which comprises reacting 100parts by weight of a polyphenylene ether consisting of the repeatingunits each represented by the general formula (I), with 1 to 5 parts byweight of a compound having an ethylenic double bond and o polar groupin the same molecule or a derivative thereof at a temperature of 300° to350° C. in the presence of 0.1 to 3 parts by weight of a radicalgenerator which exhibits a half-life period of one (1) minute at 300° C.or higher (Process II).

DESCRIPTION OF PREFERRED EMBODIMENT

There is used a styrenic polymer having a high degree of syndiotacticconfiguration as the component (A) in the thermoplastic resincomposition according to the present invention.

Here, the styrenic polymer which has a high degree of syndiotacticconfiguration means that its stereochemical structure is of a highdegree of syndiotactic configuration, i,e. the stereostructure in whichphenyl groups or substituted phenyl groups as side chains are locatedalternately at opposite directions relative to the main chain consistingof carbon-carbon bonds. Tacticity is quantitatively determined by thenuclear magnetic resonance method (¹³ C--NMR method ) using carbonisotope. The tacticity as determined by the ¹³ C--NMR method can beindicated in terms of proportions of structural units continuouslyconnected to each other, i.e., a diad in which two structural units areconnected to each other, a triad in which three structural units areconnected to each other and a pentad in which five structural units areconnected to each other. "The styrenic polymers having a high degree ofsyndiotactic configuration as mentioned in the present invention usuallymeans polystyrene, poly(alkylstyrene), poly(halogenated styrene),poly(halogenated alkylstyrene), poly(alkoxystyrene), poly(vinylbenzoate), hydrogenated polymer thereof, the mixture thereof, andcopolymers containing the above polymers as main components, having sucha syndiotacticity as determined by the above-mentioned method that theproportion of racemic diad is at least 75%, preferably at least 85%, orthe proportion of racemic pentad is at least 30%, preferably at least50%. The poly(alkylstyrene) includes poly(methylstyrene),poly(ethylstyrene), poly(isopropylstyrene), poly(tert-butylstyrene),poly(phenylstyrene), poly(vinylnaphthalene) and poly(vinylstyrene).Poly(halogenated styrene) includes poly(chlorostyrene),poly(bromostyrene) and poly(fluorostyrene). Poly(halogenatedalkylstyrene) includes poly(chloromethylstyrene). Poly(alkoxystyrene)includes poly(methoxystyrene), and poly(ethoxystyrene).

The particularly desirable styrenic polymers are polystyrene,poly(p-methylstyrene), poly(m-methylstyrene), poly(p-tert-butylstyrene),poly(p-chlorostyrene), poly(m-chlorostyrene), poly(p-fluorostyrene),hydrogenated polystyrene and the copolymer containing the structuralunits thereof such as styrene/p-methylstyrene copolymer.

The molecular weight of the styrenic polymer having a high degree ofsyndiotactic configuration to be used in the present invention is notspecifically limited, but is desirably 10,000 or more, more desirably50,000 or more in terms of weight-average molecular weight. Themolecular-weight distribution, that is, the broadening of molecularweight of the styrenic polymer is not specifically limited as well, butmay be in a wide range. A weight-average molecular weight of less than10,000 is unfavorable since the composition or molding obtained isdeteriorated thereby in the thermal and mechanical properties.

The styrenic polymer having such a high degree of syndiotacticconfiguration can be produced with reference to the technique disclosedin Japanese Patent Application Laid-Open No. 187708/1987, specificallyby polymerizing a styrenic monomer which corresponds to the abovestyrenic polymer in the presence or absence of a solvent such as aninert hydrocarbon by the use of a catalyst comprising a titaniumcompound and a condensation product of water and trialkylaluminum.

In addition, the poly(halogenated alkylstyrene) and the hydrogenatedproduct thereof can be produced by the processes described in JapanesePatent Application Laid-Open Nos. 46912/1989 and 178505/1989,respectively.

As the component (B) which is a constituent of the thermoplastic resincomposition according to the present invention, there are availablevarious kinds and forms of inorganic fillers, that is, in the form offiber, granule, powder and the like.

Examples of fibrous fiber include glass fiber, carbon fiber and whiskerin the form of cloth, mat, bound and cut fiber, short fiber, filament,whisker, etc. There is preferably used the bound and cut fiber having alength of 0.05 to 50 mm and a diameter of 5 to 20 μm.

Examples of granular or powdery filler include talc, carbon black,graphite, titanium oxide, silica, mica, calcium carbonate, calciumsulfate, barium carbonate, magnesium carbonate, magnesium sulfate,barium sulfate, oxysulfate, tin oxide, alumina, kaolin, silicon carbide,metallic powder, glass powder, glass flake and glass bead.

Any of the above-mentioned inorganic fillers may be used alone or incombination with at least one of them.

Among the above-mentioned various inorganic fillers are particularlydesirable glassy fillers including glass powder, glass flake, glassbead, glass filament, glass fiber, glass roving and glass mat.

In order to enhance the affinity between the aforestated inorganicfiller and the resin, it is effective to surface-treat said filler. Thecoupling agent to be used for the surface treatment may be optionallyselected for use from the publicly known silane-based coupling agent ofaminosilane, epoxysilane, vinylsilane, methacrylsilane series, etc. andtitanium-based coupling agent. Examples of the preferably usablecoupling agents among them include aminosilane such asγ-aminopropyltrimethoxysilane,N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane andβ-(3,4-epoxy-cyclohexyl)-ethyltrimethoxysilane, epoxysilane,isopropyltri(N-amidoethyl-aminoethyl)titanate, etc.

The surface treatment of the above-mentioned filler by the use of suchcoupling agent can be carried out by a conventional known method withoutspecific limitation.

The Maleic anhydride-modified PPO which is a constituent of thethermoplastic resin composition according to the present invention asthe component (C) and also effective for enhancing the long-term heatresistance is the Maleic anhydride-modified PPO having a modificationrate of 1.3% or more by weight which is obtained by modifying thepolyphenylene ether consisting of the repeating units each representedby the general formula (I) as described hereinbefore (hereinaftersometimes referred to as "PPO") with a compound having an ethylenicdouble bond and a polar group in the same molecule or a derivativethereof.

The PPO to be used for the Maleic anhydride-modified PPO is a publiclyknown compound, and for the purpose of the compound, reference may bemade to U.S. Pat. Nos. 3,306,874, 3,306,875, 3,257,357 and 3,257,358.

The PPO is prepared usually by oxidative coupling reaction forming ahomopolymer or a copolymer in the presence of at least member selectedfrom a cupramine complex and a mono- to tri-substituted phenol. As thecupramine complex there may be used the cupramine complex derived fromany of primary, secondary and tertiary amines.

Specific examples of the usable PPO includepoly(2,3-dimethyl-6-ethyl-1,4-phenylene ether),poly(2-methyl-6-chloromethyl-1,4-phenylene ether),poly(2-methyl-6-hydroxyethyl-1,4-phenylene ether),poly(2-methyl-6-n-butyl-1,4-phenylene ether),poly(2-ethyl-6-isopropyl-1,4-phenylene ether),poly(2-ethyl-6-n-propyl-1,4-phenylene ether), poly(2,3,6-trimethyl-I,4-phenylene ether), poly[2-(4'-methylphenyl )-1,4-phenylene ether],poly(2-phenyl-1,4-phenylene ether), poly(2-chloro-1,4-phenylene ether,poly(2-methyl-1, 4-phenylene ether), poly(2-chloro-6-ethyl-1,4-phenyleneether), poly(2-chloro-6-bromo-1,4-phenylene ether),poly(2,6-di-n-propyl-l,4-phenylene ether),poly(2-methyl-6-isopropyl-1,4-phenylene ether),poly(2-chloro-6-methyl-l,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), poly(2,6-dibromo-l,4-phenylene ether),poly(2,6-dichloro-l,4-phenylene ether), poly(2,6-diethyl-1,4-phenyleneether) and poly(2,6-dimethyl-l,4-phenylene ether). Other suitableexamples of the PPO include a copolymer derived from at least twophenolic compounds that are used for the preparation of theabove-mentioned homopolymer and a graft copolymer or a block copolymerof an aromatic vinyl compound such as polystyrene and the aforestatedpolyphenylene ether. Among the above-mentioned PPO,poly(2,6-dimethyl-1,4-phenylene ether) is particularly desirable foruse.

The degree of polymerization of the PPO is not specifically limited, butmay be suitably selected according to the purpose of use thereof,usually in the range of 60 to 400. A degree of polymerization thereofless than 60 results in little effect as a compatibilizer or an adhesiveeven if modification is carried out, whereas that exceeding 400 leads toan excessive viscosity thereof, thus causing inconvenience in handling.

In order to produce the Maleic anhydride-modified PPO from theabove-mentioned PPO, the PPO may be modified by reacting it with acompound having an ethylenic double bond and a polar Group in the samemolecule or a derivative thereof in the presence or absence of a solventor an other type of resin but in the presence of a radical generator,that is, which is known as solution modification or melt modification.

As the modifier used for modifying the PPO, there is used a compoundhaving an ethylenic double bond and a polar Group such as carboxylicgroup or acid anhydride Group in the same molecule, which isspecifically exemplified by maleic anhydride, maleic acid, maleic acidmonoester, maleic acid diester, maleimide, N-substituted compoundthereof such as N-substituted maleimide, maleic aicd monoamide andmaleic acid diamide, maleic acid ammonium salt, maleic acid metallicsalt, acrylic acid, methacrylic acid, methacrylic acid ester andglycidyl methacrylate, among which is preferably used maleic anhydridein particular.

With regard to the modification of the PPO with a compound having anethylenic double bond and a polar group in the same molecule or aderivative thereof according to the Process I, that is, solventmodification, the Maleic anhydride-modified PPO is obtained by reactingthe PPO with a compound having an ethylenic double bond and a polargroup in the same molecule or a derivative thereof in an aromatichydrocarbon solvent in the presence or absence of an other type of resinin the presence of a radical generator.

The aforementioned aromatic hydrocarbon solvent is not specificallylimited in its type insofar as it dissolves maleic anhydride or aderivative thereof and the radical generator and at the same time, inertto the radical generator. Specific preferable examples of such solventinclude benzene, toluene, ethylbenzene, xylene, chlorobenzene andtert-butylbenzene, among which are particularly desirable those having alow chain transfer constant such as benzene, toluene, chlorobenzene andtert-butylbenzene. The solvent may be used alone or as the mixture withan other solvent. The proportion of the above-mentioned solvent to beused is not specifically limited, but may be properly selected accordingto various situations. In general, the proportion may be determined inthe range of 1 to 20 times by weight based on the PPO to be used. Adeficiency in the amount of a solvent causes malfunction as the solvent,whereas an excess in the amount undesirably lowers the efficiency of theradical generator.

The proportion of a compound having an ethylenic double bond and a polargroup in the same molecule or a derivative thereof to be used as amodifier is 1 to 20, preferably 3 to 15 parts by weight per 100 parts byweight of the aforestated PPO. A proportion thereof less than 1 part byweight results in failure to sufficiently enhance the modification rate,while that exceeding 20 parts by weight necessitates sufficientpurification for the purpose of removing the excessive amount of theabove-mentioned compound, thus causing troublesome operation andunfavorable economical efficiency.

The radical generator to be used for the solution modification of thePPO with a compound having an ethylenic double bond and a polar group inthe same molecule or a derivative thereof is not specifically limited inits type, but is preferably such that has a decomposition temperaturewell suited for the reaction temperature and also a large hydrogenwithdrawing capacity in order that the above-mentioned compound or aderivative thereof may be effectively grafted onto the PPO. Such radicalgenerators are specifically exemplified by but not limited todi-tert-butyl peroxide; dicumyl peroxide; 1,1-bis(tert-butylperoxide)cyclohexane; 1,1-bis(tert-butylperoxy)3,3,5-trimethylcyclohexane; benzoyl peroxide; and decanoyl peroxide.

The proportion of the radical generator to be used therefor should be 15parts or less by weight based on 100 parts by weight of the PPO, since aproportion exceeding 15 parts by weight can unfavorably cause insolublematter.

There are available a variety of procedures for modifying the PPO.Specifically the solution modification process (Process I) comprises thesteps of dissolving the PPO and a compound having an ethylenic doublebond and a polar group in the same molecule or a derivative thereof inan aromatic hydrocarbon solvent to form a homogeneous solution; addingto the solution a radical generator at an arbitrary temperature at whichthe half-life period of the agent is not longer than one (1) hour; andproceeding with the reaction at said temperature. A reaction temperatureat which the half-life period of the agent to be used is longer than one(1) hour unfavorably necessitates a long reaction time. The modificationreaction time is properly selected, but is preferably a prescribedtemperature which is not shorter than 3 times the half-life period ofthe radical generator in order that the agent may effectively function.After the completion of the reaction, the reaction solution is added toa solvent hardly dissolving the PPO such as methanol, and the modifiedPPO thus deposited is recovered and subjected to a conventional dryingstep to afford the objective modified PPO.

On the other hand, in the melt modification process (Process II) thereis available the PPO and a compound having an ethylenic double bond apolar group in the same molecule or a derivative thereof same as thoseto be used in the above-described Process I, and the objective modifiedPPO can be produced by melt-kneading and reacting the PPO with theabove-mentioned compound or a derivative thereof at a temperature of300° to 350° C. in the presence of the radical generator.

The proportion of the above-mentioned compound or a derivative thereofto be used for the reaction is 1 to 5, preferably 2 to 4 parts by weightbased on 100 parts by weight of the PPO, since a proportion less thanone (1) part by weight is insufficient for enhancing modification rate,while that exceeding 5 parts by weight undesirably lowers theutilization efficiency of the above-mentioned compound or a derivativethereof, thus increasing the residual amount of the above-mentionedcomopund or the like in the objective pellet.

The radical generator to be employed in the melt modification process asProcess II shall be the one in which the temperature exhibiting ahalf-life period of one (1) minutes is 300° C. or higher, desirably 300°to 380° C., more desirably 300° to 350°. Such temperature as higher than380° C. sometimes results in deteriorated PPO as the product, while theaforestated temperature lower than 300° C. brings about insufficienteffect on PPO modification as is the case with a peroxide or an azocompound. There are available a variety of suitable radical generators,which are specifically exemplified by 2,3-dimethyl-2,3-diphenylbutane;2,3-diethyl-2,3-diphenylbutane; 2, 3-diethyl-2,3-diphenylhexane;2,3-dimethyl-2,3-di(p-methylphenyl)butane. Among them is most desirablyemployed 2,3-dimethyl-2,3-diphenylbutane in which the temperatureexhibiting a half-life period of one (1) minute is 330° C.

The proportion of the radical generator to be employed for the reactionis selected in the range of 0.1 to 3, preferably 0.5 to 2 parts byweight based on 100 parts by weight of the PPO, since the proportionless than 0.1 part by weight lowers the modification effect, whereasthat exceeding 3 parts by weight unfavorably deteriorates theutilization efficiency of the radical generator in the modification andsometimes causes an insoluble component.

In the melt modification process as Process II there are available avariety of procedures for modifying the PPO. Specifically, for example,the above-described PPO, a compound having an ethylenic double bond anda polar group in the same molecule or a derivative thereof and theradical generator are subjected to uniform dry-blending at roomtemperature and then to melt reaction at a temperature in the range of300° to 350° C. which is substantially the kneading temperature of thePPO. A reaction temperature lower than 300° C. results in an unfavorablehigh melting viscosity, while that higher than 350° C. undesirablycauses PPO degradation. The melt modification can be generally carriedout by melt kneading by the use of an extruder for the purpose ofmodification reaction. However, the melt modification is not limited tothe aforesaid method, but may be put into practice by a publicly knownmethod insofar as it enables the modification at a temperature in therange of 300° to 350° C. In addition, other thermoplastic resin may beadded to the composition inasmuch as the addition thereof does notimpair the effect of the present invention.

As described hereinbefore, the Maleic anhydride-modified PPO is obtainedby any of the solution modification process as Process I and the meltmodification process as Process II. In the present invention, themodification rate, which is the content of the compound having anethylenic double bond and a polar group in the same molecule in the PPOmodified with said compound is 1.3% or more, desirably 1.3 to 10%,particularly desirably 1.3 to 5% by weight as the optimum. Amodification rate of less than 1.3% by weight is unfavorable from theviewpoint of improvement in long-term heat resistance as well as theeconomical efficiency, since it necessitates increase in the compoundingratio of the Maleic anhydride-modified PPO in the composition in orderto develop sufficient dynamical properties and heat resistance. On theother hand, said rate exceeding 10% by weight sometimes unfavorablylowers the compatibility of the PPO with SPS. Thus, said rate in therange of 1.3 to 5.0% by weight is most effective for sufficientlydeveloping the dynamical properties of the composition withoutdeteriorating the long-term heat resistant stability thereof bycompounding the Maleic anhydride-modified PPO only in an small amount inthe composition.

As described hereinbefore, the thermoplastic resin composition comprisesthe above-mentioned components (A) to (C), and more specifically withregard to the compounding ratio, (A) 100 parts by weight of a styrenicpolymer having a high degree of syndiotactic configuration, (B) 1 to350, preferably 5 to 200 parts by weight of an inorganic filler and (C)0.1 to 3.5 preferably 0.5 to 3.0 parts by weight of a Maleicanhydride-modified PPO having a modification rate of 1.3% or more byweight.

In the aforestated composition, a compounding ratio of the inorganicfiller less than 1 part by weight results in failure to sufficientlyexert the compounding effect thereof, whereas that exceeding 350 partsby weight unfavorably brings about such disadvantages as poordispersibility and difficulty in molding the composition. Also, acompounding ratio of the Maleic anhydride-modified PPO less than 0.1part by weight is not sufficient to exhibit the effect on improving thedynamical properties and heat resistance of the composition, whereasthat exceeding 3.5 parts by weight undesirably results in the loss oflong-term heat resistant stability.

Moreover, the thermoplastic resin composition of the present inventioncan be further gifted with impact resistance by being compounded with arubbery elastomer when necessary as the component (D) in addition to theabove-described components (A), (B) and (C).

Examples of the rubbery elastomers capable of providing the compositionwith impact resistance include natural rubber, polybutadiene rubber,polyisoprene rubber, polyisobutylene rubber, neoprene rubber,polysulfied rubber, thiokol rubber, acrylic rubber, urethane rubber,silicone rubber, epichlorohydrin rubber, styrene/butadiene blockcopolymer, styrene/butadiene/styrene block copolymer, hydrogenatedstyrene/butadiene/styrene block copolymer, styrene/isoprene blockcopolymer, ethylene/propylene rubber, ethylene/propylene/diolefin rubberand modified products from any of the aforementioned rubbers. Among themare particularly desirably used hydrogenated styrene/butadiene/styreneblock copolymer, styrene/butadiene block copolymer,styrene/butadiene/styrene block copolymer, etc.

The compounding ratio of the rubbery elastomer is 5 to 100, preferably10 to 80 parts by weight based on 100 parts by weight of the styrenicpolymer having a high degree of syndiotactic configuration (A). Acompounding ratio thereof less than 5 parts by weight unfavorably leadsto insufficient effect on improving impact resistance, whereas thatexceeding 100 parts by weight undesirably causes marked decrease in heatresistance and rigidity of the objective composition.

Moreover, the thermoplastic resin composition according to the presentinvention may be compounded with an other type of thermoplastic resinand further any of various additives insofar as an object of the presentinvention is not impaired. The compounding ratio of the other type ofthermoplastic resin may be properly selected according to the situation,but is preferably 150 or less parts by weight based on 100 parts byweight of SPS. Examples of such resin include styrenic resin, polyolefinand polyamide, and those of the additives include antioxidant,nucleating agent, etc.

The thermoplastic resin according to the present invention is greatlyimproved in long-term heat resistant stability, which is furtherimproved along with impact resistance by the combined use with therubbery elastomer.

Consequently the thermoplastic resin composition according to thepresent invention can find a wide variety of effective use in moldingindustrial materials including electric and electronic materials such asconnectors and print-curcuit board; industrial construction materials;automobile parts such as connectors to be mounted on vehicles, wheel,cap and cylinder head cover; domestic electrical appliances; variousmachine parts, etc.

In the following, the present invention will be described in more detailwith reference to preparation examples, examples and comparativeexamples.

PREPARATION EXAMPLE 1

One (1) kg of PPO and 30 g of maleic anhydride were dry-blended and meltkneaded by the use of a 30 mm twin-screw extruder at a revolution of 200rpm at a temperature set to 300° C., while the resin temperature wasabout 330° C. The resultant strand was cooled and then pelletized toproduce maleic anhydride-modified PPO.

In order to measure the modification rate, 1 g of the resultant modifiedPPO was dissolved in chloroform and thereafter reprecipitated inmethanol, and the recovered polymer was subjected to Soxhlet extractionusing methanol and dried. The modification rate was determined from theintensity of carbonyl absorption in infrared (IR) absorption spectrumand by neutralizing titration. The results are given in Table 1.

PREPARATION EXAMPLE 2

The procedure in Preparation Example 1 was repeated except that 10 g of2,3-dimethyl-2,3-diphenylbutane (produced by Nippon 0il & Fat Co., Ltd.under the tradename NOPHMER BC) was dry blended as the radicalgenerator. The results are given in Table 1.

PREPARATION EXAMPLE 3

The procedure in Preparation Example 2 was repeated except that 20 g ofthe agent was dry blended instead of 10 g. The results are given inTable 1.

                  TABLE 1                                                         ______________________________________                                        Amount of                  Amount of                                          maleic                     radical   Modifi-                                  anhydride     Type of      generator cation                                   added         radical      added     rate                                     (phr)         generator    (phr)     (wt %)                                   ______________________________________                                        Prepara-                                                                              3           --         --      0.83                                   tion                                                                          Example 1                                                                     Prepara-                                                                              3         2,3-dimethyl-2,3-                                                                          1.0     1.35                                   tion              diphenylbutane                                              Example 2                                                                     Prepara-                                                                              3         2,3-dimethyl-2,3-                                                                          2.0     1.67                                   Example 3         diphenylbutane                                              ______________________________________                                    

EXAMPLE 1

To 100 parts by weight of syndiotactic polystyrene (SPS, weight-averagemolecular weight=348,000, weight-average molecular weight Mw/numberaverage molecular weight Mn=2.64) were added 0.5 part by weight of themaleic anhydride-modified PPO as obtained in Preparation Example 2, one(1) part by weight of aluminum p-(tert-butyl)benzoate (produced byDainippon Ink & Chemicals, Inc. under the tradename PTBBA-A1) as thenucleating agent, 0.1 part by weight of(2,6-di-tert-butyl-4-methylphenyl )pentaerythritol diphosphite (producedby Adeka Argus Co., Ltd. under the tradename "PEP-36") as an antioxidantand 0.1 part by weight of tetrakis [methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl )]-propionate (produced by Adeka ArgusCo., Ltd. under the tradename "MARK A060") also as an antioxidant, anddry blended with a Henschel mixer. Subsequently the mixture wasincorporated with 43 parts by weight of aminosilane-treated glass fiber(13 μm/3 mm) as the inorganic filler by side feeding and pelletized witha twin-screw extruder. The pellet was injection molded to produce testpieces for tensile test, which were subjected to tensile strength testsbefore and after the test for long-term heat resistance according toJIS-K-7113. The results are given in Table 2.

EXAMPLE 2 TO 6 AND COMPARATIVE EXAMPLE 1 TO 5

The procedure in Example 1 was repeated except that the amounts ofmaleic anhydride-modified PPO were altered. The results are given inTable 2.

                                      TABLE 2                                     __________________________________________________________________________                            Glass                                                                             Weight-average                                           Maleic anhydride-modified PPO                                                                  fiver                                                                             molecular                                                                              Tensile strength                                      modification                                                                         amount                                                                            amount                                                                            weight of SPS                                                                          kg/cm.sup.2                                           rate   added                                                                             added                                                                             initial                                                                           150° C.                                                                     initial                                                                           150° C.                              type  wt %   phr phr value                                                                             1,500 hr                                                                           value                                                                             1,500 hr                             __________________________________________________________________________    Example 1                                                                            Production                                                                          1.35   0.5 43  348,000                                                                           239,000                                                                            1,100                                                                             1,050                                       Example 2                                                              Example 2                                                                            Production                                                                          1.35   1.5 43  348,000                                                                           229,000                                                                            1,200                                                                             1,130                                       Example 2                                                              Example 3                                                                            Production                                                                          1.35   3.0 43  348,000                                                                           213,000                                                                            1,280                                                                             1,200                                       Example 2                                                              Example 4                                                                            Production                                                                          1.67   0.5 43  348,000                                                                           240,000                                                                            1,200                                                                             1,100                                       Example 3                                                              Example 5                                                                            Production                                                                          1.67   1.5 43  348,000                                                                           227,000                                                                            1,290                                                                             1,230                                       Example 3                                                              Example 6                                                                            Production                                                                          1.67   3.0 43  348,000                                                                           212,000                                                                            1,300                                                                             1,260                                       Example 3                                                              Comparative                                                                            --  --     0   43  348,000                                                                           250,000                                                                              990                                                                               810                                Example 1                                                                     Comparative                                                                          Production                                                                          0.83   5.0 43  348,000                                                                           162,000                                                                            1,250                                                                               760                                Example 2                                                                            Example 1                                                              Comparative                                                                          Production                                                                          0.83   10.0                                                                              43  348,000                                                                            72,000                                                                            1,250                                                                               680                                Example 3                                                                            Example 1                                                              Comparative                                                                          Production                                                                          1.67   5.0 43  348,000                                                                           158,000                                                                            1,320                                                                             1,130                                Example 4                                                                            Example 3                                                              Comparative                                                                          Production                                                                          1.67   10.0                                                                              43  348,000                                                                            75,000                                                                            1,310                                                                               900                                Example 5                                                                            Example 3                                                              __________________________________________________________________________

It can be seen from Tables 1 and 2 that the dynamical properties of thecomposition can be improved by adding 0.1 to 3.5 parts by weight ofmaleic anhydride-modified PPO as compared with the comparative exampleswithout the addition thereof, and the long-term heat resistance isimproved as compared with the comparative examples with the additionthereof of 5 or more parts by weight.

It can also be seen from the tables that the dynamical properties of thecomposition can be economically improved to a great extent by adding themaleic anhydride-modified PPO having a modification rate of 1.3% or moreby weight and at the same time the long-term heat resistance is markedlyimproved as compared with the cases with the addition thereof of 5 ormore parts by weight.

EXAMPLE 7

To 100 parts by weight of syndiotactic polystyrene (SPS, weight-averagemolecular weight=348,000, weight-average molecular weight Mw/numberaverage molecular weight Mn=2.64) were added 10 parts by weight ofhydrogenated styrene/butadiene/styrene block copolymer (produced byShell Chem. Co. under the tradename "Kraton" G1651, SEBS), 0.5 part byweight of the maleic anhydride-modified PPO as obtained in PreparationExample 2, one (1) part by weight of aluminum p-(tert-butyl) benzoate(produced by Dainippon Ink & Chemicals, Inc. under the tradenamePTBBA-A1) as the nucleating agent, 0.1 part by weight of(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite (producedby Adeka Argus Co., Ltd. under the tradename "PET-36") as an antioxidantand 0.1 part by weight oftetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)]propionate(produced by Adeka Argus Co., Ltd. under the tradeneme "MARK A060") alsoas an antioxidant, and dry blended with a Henschel mixer. Subsequentlythe mixture was incorporated with 43 parts by weight ofaminosilane-treated glass fiber (13 μm/3 mm) as the inorganic filler byside feeding and pelletized with a twin-screw extruder. The pellet wasinjection molded to produce test pieces for tensile test and Izod impacttest, which were subjected to tensile strength tests and Izod impacttests before and after the test for long-term heat resistance. Theresults are given in Table 3.

EXAMPLE 8 TO 12 AND COMPARATIVE EXAMPLES 6 TO 10

The procedure in Example 7 was repeated except that the amounts ofmaleic anhydride-modified PPO were altered. The results are given inTable 3. The tensile strength test and Izod impact strength test werecarried out in accordance with JIS-K-7113 and JIS-K-7110, respectively.

                                      TABLE 3                                     __________________________________________________________________________                             Glass    Weight-average                                     Maleic anhydride-modified PPO                                                                   fiver                                                                             SEBS molecular Tensile strength                                                                       Impact strength                       modification                                                                          amount                                                                            amount                                                                            amount                                                                             weight of SPS                                                                           kg/cm.sup.2                                                                            kg cm/cm                              rate    added                                                                             added                                                                             added                                                                              initial                                                                           150° C.                                                                      initial                                                                           150° C.                                                                     initial                                                                            150° C.             type  wt %    phr phr phr  value                                                                             1,500 hr                                                                            value                                                                             1,500 hr                                                                           value                                                                              1,500               __________________________________________________________________________                                                              hr                  Example 7                                                                            Production                                                                          1.35    0.5 43  10   348,000                                                                           239,000                                                                             1,250                                                                             1,120                                                                              10.3 9.5                        Example 2                                                              Example 8                                                                            Production                                                                          1.35    1.5 43  10   348,000                                                                           227,000                                                                             1,330                                                                             1,240                                                                              11.8 11.2                       Example 2                                                              Example 9                                                                            Production                                                                          1.35    3.0 43  10   348,000                                                                           214,000                                                                             1,420                                                                             1,310                                                                              13.6 13.2                       Example 2                                                              Example 10                                                                           Production                                                                          1.67    0.5 43  10   348,000                                                                           241,000                                                                             1,400                                                                             1,240                                                                              12.1 11.2                       Example 3                                                              Example 11                                                                           Production                                                                          1.67    1.5 43  10   348,000                                                                           225,000                                                                             1,420                                                                             1,320                                                                              13.4 12.9                       Example 3                                                              Example 12                                                                           Production                                                                          1.67    3.0 43  10   348,000                                                                           212,000                                                                             1,430                                                                             1,340                                                                              14.0 13.6                       Example 3                                                              Comparative                                                                            --  --      0   43  10   348,000                                                                           250,000                                                                               950                                                                               840                                                                              7.5  7.2                 Example 6                                                                     Comparative                                                                          Production                                                                          0.83    5.0 43  10   348,000                                                                           161,000                                                                             1,360                                                                               750                                                                              13.5 6.4                 Example 7                                                                            Example 1                                                              Comparative                                                                          Production                                                                          0.83    10.0                                                                              43  10   348,000                                                                            72,000                                                                             1,430                                                                               620                                                                              13.9 3.2                 Example 8                                                                            Example 1                                                              Comparative                                                                          Production                                                                          1.67    5.0 43  10   348,000                                                                           160,000                                                                             1,460                                                                             1,130                                                                              14.5 6.3                 Example 9                                                                            Example 3                                                              Comparative                                                                          Production                                                                          1.67    10.0                                                                              43  10   348,000                                                                            75,000                                                                             1,450                                                                               990                                                                              14.8 3.4                 Example 10                                                                           Example 3                                                              __________________________________________________________________________

It can be seen from Table 3 that the dynamical properties of thecomposition can be improved by adding 0.1 to 3.5 parts by weight ofmaleic anhydride-modified PPO as compared with the comparative exampleswithout the addition thereof, and the long-term heat resistance isimproved as compared with the comparative examples with the additionthereof of 5 or more parts by weight.

It can also be seen from the tables that the dynamical propertise of thecomposition can be economically improved to a great extent by adding themaleic anhydride-modified PPO having a modification rate of 1.3% or moreby weight and at the same time the long-term heat resistance is markedlyimproved as compared with the cases with the addition thereof of 5 moreparts by weight.

EXAMPLE 13

100 g of PPO having an intrinsic viscosity [η] of 0.47 dl/g as measuredin chloroform at 25° C. and 10 g of maleic anhydride were dissolved in150 ml of toluene with heating up to 110° C., and the resultant solutionwas incorporated with 5.0 g of 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane (produced by Nippon Oil and Fats Co., Ltd.under the tradename "PERHEXA-3M") to proceed with modification reactionfor 4 hours. The resultant reaction solution was added to one (1) literof methanol to recover the deposited polymer.

The presence of unmodified PPO was judged by dissolving one (1) g of therecovered polymer in 50 ml of methylene chloride, allowing the solutionto stand for 3 hours and observing the presence of deposit, and also bythin-layer chromatography using silica gel along with the existence ofimpurities. The modification rate of the polymer thus obtained wasdetermined by dissolving one (1) g of the resultant modified PPO inchloroform, reprecipitating it in methanol, subjecting the recoveredpolymer to Soxhlet extraction using methanol, drying the polymer,measuring the intensity of carbonyl absorption in infrared (IR)absorption spectrum and conducting neutralizing titration. The resultsare given in Table 4.

The modification rate of the modified PPO was determined fromneutralizing titration in accordance with the following procedures.

Procedure (1)

One (1) g of the modified PPO after drying was dissolved in the mixedsolvent of 100 ml of chloroform and 20 ml of ethanol each had beendehydrated with molecular sieve. To the solution thus obtained was addedphenolphthalein as the titration indicator and the resultant solutionwas titrated with 0.05 N solution of potassium hydroxide in ethanol(titration solution) until neutral with the indicator to obtain thequantity of the titration solution required for neutralization (K₁).

Procedure (2)

The procedure in Procedure (1) was repeated except that unmodified PPOwas employed in place of the modified PPO to obtain the quantity of thetitration solution required for neutralization (k₂).

Procedure (3)

The procedure in Procedure (1) was repeated except that succimicanhydride was used in place of the modified PPO to determine theneutralization equivalent for the titration solution of the modified PPO(maleic anhydride-modified PPO). As the result, it was proved that aboutone (1) equivalent of potassium hydroxide was necessary per one (1)equivalent of succinic anhydride. The reason for using succinicanhydride in the procedure is that maleic anhydride is presumed to reactwith PPO and saturate C═C bond thereof into C--C bond.

Procedure (4 )

The titre for the Groups derived from maleic anhydride in PPO (K)(herein after simply referred to as "maleic anhydride Groups") wasobtained by substracting the quantity of the titration solution requiredin Procedure (2) (K₁) from that required in Procedure (1) (K₁) asexpressed by the following formula:

    K=K.sub.1 -K.sub.2

On the basis of the result in Procedure (3) that in neutralizing themaleic anhydride Groups in the modified PPO, one (1) equivalent ofpotassium hydroxide is necessary per one (1) equivalent of maleicanhydride Groups, the quantity of maleic anhydride Groups in themodified PPO was calculated. The modification rate of the modified PPOwas obtained as the ratio in % by weight of the quantity of maleicanhydride Groups calculated in the above manner to the modified PPO.Example 14

The procedure in Example 13 was repeated except that the amount of thePERHEXA-3M was altered. The results are given in Table 4.

EXAMPLES 15 TO 16

The procedure in Example 13 was repeated except that ethylbenzene wasused as the solvent in place of toluene, a different amount ofdi-tert-butyl peroxide (produced by Nippon Oil & Fats Co., Ltd. underthe tradename "PERBUTYL-D") was used as the radical generating agent inplace of 1,1-bis(tert-butylperoxy )-3,3,5-trimethylcyclohexane, and thereaction was carried out at 145° C. The results are given in Table 4.

COMPARATIVE EXAMPLE 10

The procedure in Example 13 was repeated except that 1 kg of PPO same asthat in Example 13 was dry blended with 50 g of maleic anhydride at roomtemperature and the resultant blend was subjected to modificationreaction by melt kneading at 300° C. by the use of a 30 mm twin-screwextruder. The results are given in Table 4.

COMPARATIVE EXAMPLE 11

The procedure in Comparative Example 10 was repeated except that dicumylperoxide (produced by Nippon Oil & Fats Co., Ltd. under the tradename"PERCUMYL-D") was added to the composition. The results are given inTable 4.

                                      TABLE 4                                     __________________________________________________________________________                           Amount of                                                                           Modifi-                                                                           Presence                                                   Type of  radical                                                                             cation                                                                            of un-                                              Modification                                                                         radical  generator                                                                           rate                                                                              modified                                            method generator                                                                              added (phr)                                                                         (wt %)                                                                            PPO.sup.1)                                                                         Impurity.sup.2)                                                                     Hue.sup.3)                        __________________________________________________________________________    Example 13                                                                           solution                                                                             PERHEXA-3M                                                                             5.0   1.77                                                                              ⊚                                                                   ⊚                                                                    ⊚                         modification                                                           Example 14                                                                           solution                                                                             PERHEXA-3M                                                                             10.0  3.39                                                                              ⊚                                                                   ⊚                                                                    ∘                            modification                                                           Example 15                                                                           solution                                                                             PERBUTYL-D                                                                             5.0   1.54                                                                              ⊚                                                                   ∘                                                                       ⊚                         modification                                                           Example 16                                                                           solution                                                                             PERBUTYL-D                                                                             10.0  3.01                                                                              ⊚                                                                   ∘                                                                       ∘                            modification                                                           Comparative                                                                          melt   none     0     0.83                                                                              x    x     Δ                           Example 10                                                                           modification                                                           Comparative                                                                          melt   PERCUMYL-D                                                                             1.0   0.78                                                                              x    x     x                                 Example 11                                                                           modification                                                           __________________________________________________________________________     .sup.1) Amount of unmodified PPO deposited   little ⊚ <        ∘ < Δ < x much                                              .sup.2) Amount of impurities   little ⊚ < ∘ <      Δ < x much                                                              .sup.3) Visual observation   good ⊚ < ∘ <          Δ  < x bad                                                         

It can be seen from Table 4 that it is made possible by the solutionmodification to increase the modification rate of PPO, decreaseimpurities and residual unmodified PPO and improve the hue of theobjective product.

EXAMPLE 17

100 parts by weight of SPS having a weight-average molecular weight (Mw)of 400,000 and Mw/Mn ratio of 2.5 (Mn:number-average molecular weight)was dry-blended with 3 parts by weight of the maleic anhydride-modifiedPPO as prepared in Example 14, and the resultant blend was kneaded bythe use of a 30 mm twin-screw extruder at 300° C. at a revolution of 200rpm, while being fed with 43 parts by weight of aminosilane-treatedglass fiber to afford pellet. The resultant pellet was molded, and themolding thus obtained was tested for dynamical properties and heatresistance. The results are given in Table 5.

EXAMPLE 18

The procedure in Example 17 was repeated except that 0.5 part by weightof the maleic anhydride-modified PPO as prepared in Example 14 was usedinstead of 3 parts by weight. The test results are given in Table 5.

COMPARATIVE EXAMPLE 12

The procedure in Example 17 was repeated except that 3 parts by weightof the maleic anhydride-modified PPO as prepared in Comparative Example10 was used. The test results are given in Table 5.

COMPARATIVE EXAMPLE 13

The procedure in Example 17 was repeated except that 0.5 part by weightof the maleic anhydride-modified PPO as prepared in Comparative Example10 was used. The test results are given in Table 5.

                                      TABLE 5                                     __________________________________________________________________________                       Izod   Flexural                                                                            Heat distortion                                                                           Long-term heat                           Modification                                                                         Amount                                                                             impact modulus of                                                                          temperature resistance                               rate of PPO                                                                          added                                                                              strength.sup.1)                                                                      elasticity.sup.2)                                                                   at high load.sup.3)                                                                       at 130° C..sup.5)                 (wt %) (phr)                                                                              (kg · cm/cm)                                                                (kg/cm.sup.2)                                                                       (°C.)                                                                          Hue.sup.4)                                                                        (1000 hr)                         __________________________________________________________________________    Example 17                                                                           3.39   3.0  11.1   104000                                                                              257     ∘                                                                     ∘                     Example 18                                                                           3.39   0.5  7.9    106000                                                                              254     ∘                                                                     ∘                     Comparative                                                                          0.83   3.0  11.0   104000                                                                              257     x                                     Example 12                                                                    Comparative                                                                          0.83   0.5  5.9    102000                                                                              247         ∘                     Example 13                                                                    __________________________________________________________________________     .sup.1) According to JISK-7110                                                .sup.2) According to JISK-7203                                                .sup.3) According to JISK-7207 (18.6 kg/cm.sup.2)                             .sup.4) Visual observation   good ⊚ < ∘ <          Δ < x bad                                                               .sup.5) Retention ot tensile strength                                    

It is clear from Table 5 that the increased modification rate and thedecreased impurities by virture of the solution modification process(Process I) are effective for improving the dynamical properties, hueand heat resistant stability of the glass fiber-reinforced thermoplasticresin.

Since as mentioned above the modified PPO obtained by the Process I isenhanced in modification rate and free from impurities, only a smallamount of the above PPO added to a styrenic polymer alloy or acomposition thereof can improve the dynamical properteis and heatresistance, and as compared with the prior arts, the heat resistantstability as well.

EXAMPLE 19

One (1) kg of PPO same as that in Example 13, 30 g of maleic anhydrideand 10 g of 2,3-dimethyl-2,3-diphenylbutane (produced by Nippon Oil &Fats Co., Ltd. under the tradename "NOPHMER BC") as the radicalGenerator were dry-blended and melt-kneaded by the use a 30 mmtwin-screw extruder at a revolution of 200 rpm at a temperature set to300° C., while the resin temperature was 300° C., approximately. Theresultant strand was cooled and then pelletized to produce maleicanhydride-modified PPO.

In order to measure the modification rate, one (1) g of the resultantmodified PPO was dissolved in chloroform and thereafter reprecipitatedin methanol, and the recovered polymer was subjected to Soxhletextraction and dried. The modification rate was determined from theintensity of carbonyl absorption in IR absorption spectrum and bynectralizing titration. The results are Given in Table 6.

EXAMPLES 20 TO 22

The procedure in Example 19 was repeated except that the amounts of themaleic anhydride-modified PPO and NOPHMER BC were altered as in Table 6.The test results are given in Table 6.

COMPARATIVE EXAMPLE 14

The procedure in Example 19 was repeated except that any radicalgenerator was not added. The test results are given in Table 6.

COMPARATIVE EXAMPLE 15

The procedure in Example 19 was repeated except that 50 g of maleicanhydride was added and any radical generator was not added. The testresults are given in Table 6.

COMPARATIVE EXAMPLES 16 TO 23

The procedure in Example 19 was repeated except that the amounts ofmaleic anhydride added and the types of radical generators were altered.The test results are given in Table 6.

                  TABLE 6                                                         ______________________________________                                        Amount of                  Amount of                                          maleic                     radical   Modifi-                                  anhydride     Type of      generator cation                                   added         radical      added     rate                                     (phr)         generator    (phr)     (wt %)                                   ______________________________________                                        Example 19                                                                            3         2,3-dimethyl-2-3-                                                                          1.0     1.35                                                     diphenylbutane                                              Example 20                                                                            3         2-3-dimethyl-2-3-                                                                          2.0     1.67                                                     diphenylbutane                                              Example 21                                                                            5         2,3-dimethyl-2,3-                                                                          1.0     1.45                                                     diphenylbutane                                              Example 22                                                                            5         2,3-dimethyl-2,3-                                                                          2.0     1.98                                                     diphenylbutane                                              Compara-                                                                              3           --         --      0.83                                   tive                                                                          Example 14                                                                    Compara-                                                                              5           --         --      0.92                                   tive                                                                          Example 15                                                                    Compara-                                                                              3         benzoyl peroxide                                                                           1.0     0.80                                   tive                                                                          Example 16                                                                    Compara-                                                                              3         dicumyl peroxide                                                                           1.0     0.78                                   tive                                                                          Example 17                                                                    Compara-                                                                              3         di-tert-butyl                                                                              1.0     0.81                                   tive              peroxide                                                    Example 18                                                                    Compara-                                                                              3         cumene hydro-                                                                              1.0     0.81                                   tive              peroxide                                                    Example 19                                                                    Compara-                                                                              3         tert-butyl   1.0     0.85                                   tive              hydroperoxide                                               Example 20                                                                    Compara-                                                                              3         1,1,3,3,-tetra-                                                                            1.0     0.86                                   tive              methylbutyl                                                 Example 21        hydroperoxide                                               Compara-                                                                              3         azobis(isobutyro)                                                                          1.0     0.80                                   tive              nitrile                                                     Example 22                                                                    Compara-                                                                              3         1,1',-azobis(cyclo-                                                                        1.0     0.84                                   tive              hexane-1-                                                   Example 23        carbonitrile)                                               ______________________________________                                    

As is clear from the results in Table 6, the modification rate of themaleic anhydride-modified PPO can be improved by the addition of aradical generator. However, as is clear from the results in ComparativeExamples 16 to 23, the use of the peroxide or azo compound which hasheretofore been employed as a radical generator and is instantaneouslydecomposed at the PPO's substantial kneading temperature does verylittle in contributing to the modification of PPO. On the other hand,even a small amount of 2,3-dimethyl-2,3-diphenylbutane, when used as theradical generator in the present invention (Process II), can remarkablyimprove the modification rate and facilitates the production of themaleic anhydride-modified PPO at a modification rate higher than that inthe conventional method by the use of a simplified extruder.

EXAMPLE 23

100 parts by weight of SPS having a Mw of 400,000 and Mw/Mn ratio of 2.5was dry-blended with one (1) part by weight of the maleicanhydride-modified PPO as prepared in Example 19, and the resultantblend was kneaded by the use of a 30 mm twin-screw extruder at 300° C.at a revolution of 200 rpm, while being fed with 43 parts by weight ofaminosilane-treated glass fiber to produce pellet. The pellet thusobtained was molded, and the resultant molding was tested for dynamicalproperteis and heat resistance. The results are given in Table 7.

EXAMPLE 24

The procedure in Example 23 was repeated except that one (1) part byweight of the maleic anhydride-modified PPO as prepared in Example 20was employed. The test results are given in Table 7.

COMPARATIVE EXAMPLES 24 AND 25

The procedure in Example 23 was repeated except that one (1) part byweight of the maleic anhydride-modified PPO as prepared in ComparativeExamples 18 and 21, respectively was employed. The test results aregiven in Table 7.

                                      TABLE 7                                     __________________________________________________________________________           Modification                                                                              Izod impact strength Heat distortin                               rate of                                                                              Amount                                                                             with   without                                                                              Flexual                                                                              temperature                                  PPO    added                                                                              notch  notch  strength.sup.2)                                                                      at high load.sup.3)                          (wt %) (phr)                                                                              (kg · cm/cm)                                                                (kg · cm/cm)                                                                (kg · cm/cm.sup.2)                                                          (°C.)                          __________________________________________________________________________    Example 23                                                                           1.45   1.0  9.5    42     1870   257                                   Example 24                                                                           1.67   1.0  10.1   44     1890   257                                   Comparative                                                                          0.80   1.0  7.5    31     1680   253                                   Example 24                                                                    Comparative                                                                          0.87   1.0  7.5    32     1700   254                                   Example 25                                                                    __________________________________________________________________________     .sup.1) According to JISK-7110                                                .sup.2) According to JISK-7203                                                .sup.3) According to JISK-7207 (18.6 kg/cm.sup.2)                        

As is clear from the test results in Table 7, increased modificationrate of PPO even at the same amount thereof enables the manifestation ofthe dynamical properties and heat resistance of the objectivecomposition that are superior to those of the conventional product,thereby making contributions to the improvement in adhesion betweenSPS-based resin and inorganic fillers in SPS-based resin compositions,as well as to the production of the modified PPO useful for the purposeof improving compatibility among the components of alloy-basedcomposition.

As described above, the melt modification process (Process II) accordingto the present invention enables the production of the modified PPOenhanced in modification rate with simplified operation by the use ofthe radical generating agent having a decomposition temperature higherthan those of the conventional agent. Likewise, the modified PPOproduced by the Process II is capable of improving the dynamicalproperties and heat resistance of a styrenic polymer alloy or thecomposition thereof only by a small amount added to said alloy or thecomposition.

EXAMPLE 25

The procedure in Example 14 was repeated except that glycidylmethacrylate was used in place of maleic anhydride. The results aregiven in Table 8.

COMPARATIVE EXAMPLE 26

The procedure in Comparative Example 10 was repeated except thatglycidyl methacrylate was used in place of maleic anhydride. The resultsare given in Table 8.

                                      TABLE 8                                     __________________________________________________________________________                          Amount of                                                             Type of radical                                                                             Modification                                                                         Presence of                                       Modification                                                                         radical generator                                                                           rate   unmodified                                        method generator                                                                             (phr) (wt %) PPO   Impurity                                                                           Hue                             __________________________________________________________________________    Example 25                                                                           solution                                                                             PERHEXA-3M                                                                            10.0  3.01   ⊚                                                                    ⊚                                                                   ∘                          modification                                                           Comparative                                                                          melt   none    --    0.77   x     x    Δ                         Example 26                                                                           modification                                                           __________________________________________________________________________     Note;                                                                         Each symbol is as defined in Table 4.                                    

EXAMPLE 26

The procedure in Example 17 was repeated except that 3 parts by weightof the glycidyl methacrylate-modified PPO as prepared in Example 25 wasused. The results are given in Table 9.

COMPARATIVE EXAMPLE 27

The procedure in Example 17 was repeated except that 3 parts by weightof the glycidyl methacrylate-modified PPO as prepared in ComparativeExample 26 was used. The results are given In Table 9.

                                      TABLE 9                                     __________________________________________________________________________                       Izod   Flexural                                                                            Heat                                                 Modificatin                                                                          Amount                                                                             Impact modulus of                                                                          distortion Long-term                                 rate of PPO                                                                          added                                                                              strength                                                                             elasticity                                                                          temperature at                                                                           heat                                      (wt %) (phr)                                                                              (kg · cm/cm)                                                                (kg/cm.sup.2)                                                                       high load (°C.)                                                                Hue                                                                              resistance                         __________________________________________________________________________    Example 26                                                                           3.01   3.0  10.5   102000                                                                              256     ∘                                                                    ∘                      Comparative                                                                          0.77   3.0  10.8   102000                                                                              255     x  Δ                            Example 27                                                                    __________________________________________________________________________     Note;                                                                         Each symbol is as defined in Table 5.                                    

EXAMPLE 27

The procedure in Example 19 was repeated except that glycidylmethacrylate was used in place of maleic anhydride. The results aregiven in Table 10.

COMPARATIVE EXAMPLE 28

The procedure in Comparative Example 17 was repeated except thatglycidyl methacrylate was used in place of maleic anhydride. The resultsare Given in Table 10.

                  TABLE 10                                                        ______________________________________                                        Amount of                  Amount of Modifi-                                  glycidyl                   radical   cation                                   methacrylate  Type of radical                                                                            generator rate                                     (phr)         generator    (phr)     (wt %)                                   ______________________________________                                        Ex-    3          2,3-dimethyl-2,3-                                                                          1.0     1.60                                   ample 27          diphenylbutane                                              Compar-                                                                              3          dicumyl peroxide                                                                           1.0     0.80                                   ative Ex-                                                                     ample 28                                                                      ______________________________________                                    

EXAMPLE 28

The procedure in Example 23 was repeated except that 1 part by weight ofthe glycidyl methacrylate-modified PPO as prepared in Example 27 wasused. The results are given in Table 11.

COMPARATIVE EXAMPLE 29

The procedure in Example 23 was repeated except that 1 part by weight ofthe glycidyl methacrylate-modified PPO as prepared in ComparativeExample 28 was use. The results are given in Table 11.

                                      TABLE 11                                    __________________________________________________________________________           Modification                                                                         Amount                                                                             Izod impact strength                                                                       Flexural                                                                             Heat distortin                                rate of PPO                                                                          added                                                                              (kg · cm/cm)                                                                      strength                                                                             temperature at                                (wt %) (phr)                                                                              with notch                                                                          without notch                                                                        (kg · cm/cm.sup.2)                                                          high load (°C.)                 __________________________________________________________________________    Example 28                                                                           1.60   1.0  9.8   40     1850   256                                    Comparative                                                                          0.80   1.0  7.0   33     1660   252                                    Example 29                                                                    __________________________________________________________________________

What is claimed is:
 1. A thermoplastic resin composition which comprises (A) 100 parts by weight of a styrenic polymer having a high degree of syndiotactic configuration, (B) 1 to 350 parts by weight of an inorganic filler and (C) 0.1 to 3.5 parts by weight of a polyphenylene ether that is modified with a compound having an ethylenic double bond and a polar group in the same molecule, said ether having a modification rate of 1.3% to 10% by weight.
 2. A thermoplastic resin composition which comprises (A) 100 parts by weight of a styrenic polymer having a high degree of syndiotactic configuration, (B) 1 to 350 parts by weight of an inorganic filler, (D) 5 to 100 parts by weight of a rubbery elastomer and (C) 0.1 to 3.5 parts by weight of a polyphenylene ether that is modified with a compound having an ethylenic double bond and a polar group in the same molecule, said ether having a modification rate of 1.3% to 10% by weight.
 3. The composition according to claim 1 wherein the inorganic filler is a surface-treated inorganic filler.
 4. The composition according to claim 2 wherein the inorganic filler is a surface-treated inorganic filler.
 5. The composition according to claim 1 wherein said compound is selected from maleic anhydride and glycidyl methacrylate.
 6. The composition according to claim 2 wherein said compound is selected from maleic anhydride and glycidyl methacrylate.
 7. The composition according to claim 1 which comprises the polyphenylene ether that is modified with a compound having an ethylenic double bond and a polar group in the same molecule, said ether having a modification rate of 1.3% to 10% by weight and being produced by a process which comprises reacting 100 parts by weight of a polyphenylene ether consisting of the repeating units each represented by the general formula (I) ##STR2## wherein R¹ and R² are each an alkyl group having 1 to 4 carbon atoms or a halogen atom, with 1 to 20 parts by weight of the compound having an ethylenic double bond and a polar group in the same molecule in an aromatic hydrocarbon solvent in the presence of 15 or less parts by weight of a radical generator.
 8. The composition according to claim 1 which comprises the polyphenylene ether that is modified with a compound having an ethylenic double bond and a polar group in the same molecule, said ether having a modification rate of 1.3% to 10% by weight and being produced by a process which comprises reacting 100 parts by weight of a polyphenylene ether consisting of the repeating units each represented by the general formula (I) ##STR3## wherein R¹ and R² are each an alkyl group having 1 to 4 carbon atoms or a halogen atom, with 1 to 5 parts by weight of the compound having an ethylenic double bond and a polar group in the same molecule at a temperature of 300° to 350° C. in the presence of 0.1 to 3 parts by weight of a radical generator which exhibits a half-life period of one (1) minute at 300° C. or higher.
 9. The composition according to claim 2 which comprises the polyphenylene ether that is modified with a compound having an ethylenic double bond and a polar group in the same molecule, said ether having a modification rate of 1.3% to 10% by weight and being produced by a process which comprises reacting 100 parts by weight of a polyphenylene ether consisting of the repeating units each represented by the general formula (I) ##STR4## wherein R¹ and R² are each an alkyl group having 1 to 4 carbon atoms or a halogen atom, with 1 to 20 parts by weight of the compound having an ethylenic double bond and a polar group in the same molecule in an aromatic hydrocarbon solvent in the presence of 15 or less parts by weight of a radical generator.
 10. The composition according to claim 2 which comprises the polyphenylene ether that is modified with a compound having an ethylenic double bond and a polar group in the same molecule, said ether having a modification rate of 1.3% to 10% by weight and being produced by a process which comprises reacting 100 parts by weight of a polyphenylene ether consisting of the repeating units each represented by the general formula (I) ##STR5## wherein R¹ and R² are each an alkyl group having 1 to 4 carbon atoms or a halogen atom, with 1 to 5 parts by weight of the compound having an ethylenic double bond and a polar group in the same molecule at a temperature of 300° to 350° C. in the presence of 0.1 to 3 parts by weight of a radical generator which exhibits a half-life period of one (1) minute at 300° C. or higher. 